665357753549 has 2 divisors, whose sum is σ = 665357753550. Its totient is φ = 665357753548.

The previous prime is 665357753539. The next prime is 665357753617. The reversal of 665357753549 is 945357753566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 641950283524 + 23407470025 = 801218^2 + 152995^2 .

It is a cyclic number.

It is not a de Polignac number, because 665357753549 - 2²⁰ = 665356704973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665357753539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332678876774 + 332678876775.

It is an arithmetic number, because the mean of its divisors is an integer number (332678876775).

Almost surely, 2^665357753549 is an apocalyptic number.

It is an amenable number.

665357753549 is a deficient number, since it is larger than the sum of its proper divisors (1).

665357753549 is an equidigital number, since it uses as much as digits as its factorization.

665357753549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 357210000, while the sum is 65.

The spelling of 665357753549 in words is "six hundred sixty-five billion, three hundred fifty-seven million, seven hundred fifty-three thousand, five hundred forty-nine".